Many devices are currently available for use in effecting surgical attachments, particularly in attaching objects to bone.
In some procedures, for example, a hole is first drilled in a bone, and then a suture anchor is deployed in the hole, with a suture element trailing from the suture anchor and extending out of the bone. Tissue or other objects may then be secured to the bone using the suture. In some cases the suture may extend completely around the tissue or other object which is being attached to the bone; in other cases the suture may be passed through the tissue or other object and then tied off on the far side of the tissue or object so as to effect attachment. In the case where the suture extends through the tissue or other object and is tied off on the far side thereof, various types of washers or buttons have been proposed to facilitate attachment. These washers or buttons rest against the outer surface of the tissue or other object, and improve the connection between the suture and the tissue or object.
The need for such secure attachment is particularly critical in connection with reapproximating bone of any type to another bone. This type of procedure is exemplified in applications such as joining the fibula to the tibia bone in ankle surgery, or as applied to a shoulder operation. In the case of acromioclavicular and coracoclavicular suture fixations, for example, several holes are drilled in the clavicle above the coracoid. A suture is passed beneath the base of the coracoid and superiorly through the two holes in the clavicle. Another suture is attached to the acromioclavicular ligament and then attached to the clavicle. The joint is then reduced and the sutures are tied off. Sutures such as mattress sutures may be placed in any ruptured coracoclavicular ligaments and also tied off. In addition, the ligaments may be joined to the bone by the same technique.
This procedure is significantly improved by the use of suture anchors, which can be recessed into the coracoid and the suture extended superiorly through only a single hole in the clavicle. This eliminates the need to place a suture exteriorly of the coracoid and thereby removes the possibility of the suture subsequently eroding because of motion in the shoulder.
Even with this improved procedure, however, there still remains the necessity of tying off the suture. As indicated above, conventional surgical buttons, washers or other suture retaining devices may be used, where the suture is pulled through the retaining device and tension then applied to the tissue before the suture is tied off.
One such type of suture retaining device is shown in U.S. Pat. No. 4,741,330 issued May 3, 1988 to Hayhurst. As taught in this patent, the suture retaining device is a button of resilient material having slits formed therein which cross at the center of the button, in order to create pointed bendable flaps. The suture is inserted through the center of the button and the flaps are resiliently deformed away from the plane of the button, toward the direction of movement of the suture. Thereafter, the button is urged toward the surface of the tissue which is to be joined to a bone and, after tension is applied to the suture while pushing against the button, the suture is tied off so as to hold the tissue securely against the bone.
In another type of retaining device, as exemplified by U.S. Pat. No. 4,669,473 issued Jun. 2, 1987 to Richards et al., the suture (or filament) is provided with a plurality of conically shaped ribs along its length. The ribs are formed so that the larger end of each rib faces toward the tissue or bone. Such ribs allow an associated flexible washer to be slid over the suture (or filament) and over the ribs in the direction of the tissue or bone, yet prevent the washer from slipping backward over a conically shaped rib once it has passed that rib. In this manner the washer can be brought to bear against the tissue and held there by the nearest conical rib.
In all of the known prior art suture retaining devices, there remains the drawback that the buttons or washers, as well as the suture knots, are left protruding above the superior tissue or bone surface at the conclusion of the procedure. As a result, the buttons and/or knots may cause trauma to a patient when the joint or body part is thereafter subjected to movement.
It is, therefore, one object of the present invention to provide a suture retaining device which permits the suture knot to be recessed below the top surface of the tissue or bone element which is being approximated to another bone using suture.
Another object of the present invention is to provide a suture retaining device which is itself capable of being disposed below the superior surface of the tissue or bone element which is being approximated to another bone using suture.
Still another object of the present invention is to provide a suture retaining device for use with a suture anchor, wherein both the suture knot customarily employed in tying off the suture, as well as the retaining device itself, are both embedded below the tissue or bone surface.
A further object of the present invention is to provide a suture retaining device which permits ligaments to be transversely attached to a bone by means of a side hole or holes formed in the suture retaining device.
A still further object of the present invention is to provide a suture retaining device for use in fixedly holding ligament graft material within a bone tunnel.
And another object of the present invention is to provide a suture retaining device which may be used with at least one length of suture to approximate an object to an anatomical structure.